1. Field of the Invention
The present invention relates generally to pipelined analog-to-digital converters.
2. Description of the Related Art
A variety of modern electronic systems (e.g., scanners, camcorders, communication modems, medical image processors and high-definition television) require high-speed signal conditioning which has been effectively provided with pipelined analog-to-digital converters (ADCs) whose multiple converter stages provide conversion speeds that typically exceed those of other converter structures.
In pipelined operation, it is intended that stage amplifiers provide amplifier output signals that correspond only to stage input signals. For example, an important class of pipelined ADCs is realized with converter stages that each use a switched-capacitor structure to process a respective input data signal and generate a succeeding input data signal for a succeeding converter stage.
It has been found that gain and offset errors in these switched-capacitor structures introduce nonlinearities into the pipelined converter's transfer function and various methods and structures have been proposed to reduce these errors. There remain other errors, however, which continue to degrade pipelined converter performance and sources and solutions for these errors has often not been identified.